Wait, nevermind my previous post. I figured out a logical explanation.
You traveled from the future where you had lots and lots of money to the point that 10 bucks is hardly anything, and you pre-paid for any drinks you get from the store throughout time, thus saving you lots of your own money thus giving you more money in the future. It was also to prevent a paradox from happening because you have lots of money in the future. It's a cycle, obviously. Paradoxes are so confusing.
EDIT: Actually, who knows. This is very impossible.
